package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import server.container.Context;
import server.container.Engine;
import server.container.Host;

import java.io.*;
import java.net.*;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {

        // 加载解析相关的配置，web.xml
        loadConfiguration();


        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/


        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while (true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, engine);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }


    }


//    private Map<String, HttpServlet> servletMap = new HashMap<String, HttpServlet>();

    private Engine engine = new Engine();

    private void loadConfiguration() {
        // 载入server文件
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//Host");
            Map<String, Host> hostMap = new HashMap<>();
            engine.setHostMap(hostMap);
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);

                String name = element.attribute("name").getStringValue();
                String appBase = element.attribute("appBase").getStringValue();

                // 解析host
                Host host = new Host();
                host.setName(name);
                host.setAppBase(appBase);
                Map<String, Context> contextMap = new HashMap<>();
                host.setContextMap(contextMap);
                hostMap.put(name, host);

                // 解析contexts
                File hostBase = new File(appBase);
                // 异常判断
                if (!hostBase.isDirectory()) {
                    continue;
                }
                File[] appFiles = hostBase.listFiles();
                if (appFiles == null) {
                    continue;
                }

                for (File contextBase : appFiles) {
                    // 跳过文件
                    if (!contextBase.isDirectory()) {
                        continue;
                    }
                    // 获取每个项目下的web.xml
                    File[] webXml = contextBase.listFiles((dir, name1) -> "web.xml".equals(name1));
                    if (webXml != null && webXml.length > 0) {
                        // 解析webXml
                        Context context = loadContext(contextBase.getAbsolutePath(), webXml[0]);
                        // 存入contextMap
                        contextMap.put(contextBase.getName(), context);
                    }
                }
            }


        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    /**
     * 加载解析web.xml，初始化Servlet
     */
    private Context loadContext(String contextBasePath, File webXml) throws FileNotFoundException {
        Context context = new Context();

        FileInputStream resourceAsStream = new FileInputStream(webXml);
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            Map<String, HttpServlet> servletMap = new HashMap<>();
            context.setServletMap(servletMap);

            // 获取一个用于加载当前context下class的类加载器
            URLClassLoader webAppClassLoader = getWebAppClassLoader("file://" + contextBasePath + "/");
            context.setClassLoader(webAppClassLoader);

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();

                // 使用自定义的类加载器进行加载
                servletMap.put(urlPattern, (HttpServlet) webAppClassLoader.loadClass(servletClass).newInstance());

            }

            return context;


        } catch (DocumentException | IllegalAccessException | InstantiationException | ClassNotFoundException | MalformedURLException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }

    }


    private URLClassLoader getWebAppClassLoader(String contextBase) throws MalformedURLException {
        URL url = new URL(contextBase);
        return new URLClassLoader(new URL[]{url});
    }


//    /**
//     * 加载解析web.xml，初始化Servlet
//     */
//    private void loadServlet() {
//        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
//        SAXReader saxReader = new SAXReader();
//
//        try {
//            Document document = saxReader.read(resourceAsStream);
//            Element rootElement = document.getRootElement();
//
//            List<Element> selectNodes = rootElement.selectNodes("//servlet");
//            for (int i = 0; i < selectNodes.size(); i++) {
//                Element element = selectNodes.get(i);
//                // <servlet-name>lagou</servlet-name>
//                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
//                String servletName = servletnameElement.getStringValue();
//                // <servlet-class>server.LagouServlet</servlet-class>
//                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
//                String servletClass = servletclassElement.getStringValue();
//
//
//                // 根据servlet-name的值找到url-pattern
//                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
//                // /lagou
//                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
//                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
//
//
//            }
//
//
//        } catch (DocumentException e) {
//            e.printStackTrace();
//        } catch (IllegalAccessException e) {
//            e.printStackTrace();
//        } catch (InstantiationException e) {
//            e.printStackTrace();
//        } catch (ClassNotFoundException e) {
//            e.printStackTrace();
//        }
//
//    }


    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
